As shown in FIG. 1, a front wheel 2 of the prior art children tricycle is provided in the center thereof with a through hole 21 in which a crank rod 3 is fastened by welding. The front wheel 2 of the prior art described above is defective in design in that the crank rod 3 is not fastened securely with the through hole 21 by welding, and that the welding method of fastening the crank rod 3 with the through hole 21 of the prior art front hub is time-consuming and ineffective at best